It has been demonstrated that cancerous cells are more resistant to fluid shear stress than normal (non-cancerous) cells. (See, Barnes J. M., Nauseef, J. T., Henry, M. D. (2012) Resistance to Fluid Shear Stress Is a Conserved Biophysical Property of Malignant Cells. PLoS ONE 7(12): e50973. doi:10.1371/journal.pone.0050973.) In particular, the repeated exposure of fluid samples comprising both cancerous and normal cells to a fluid shear stress has been found to impart a selective resistance to the fluid shear stress to the cancerous cells and to selectively kill the non-cancerous cells, thereby providing a fluid sample enriched in the cancerous cells. (Id.) The concentration and isolation of fluid shear stress-resistant cancerous cells allows for further characterization of the cancerous cells, ultimately leading to improved clinical diagnostic tests for prognostic and therapeutic applications.